JPH0159154B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine and an outboard motor in which an oil pan thereof is attached to the upper end of a casing via a spacer.

Generally, an outboard motor has a structure in which a cowling is attached to the upper end of a casing, and an internal combustion engine is disposed within this cowling, and the internal combustion engine is usually rigidly mounted to an opening at the upper end of the casing.

By the way, when a four-stroke internal combustion engine is used as the internal combustion engine, this internal combustion engine is equipped with an oil pan for storing lubricating oil.
This oil pan is located at the lowest part of the cylinder block or crankcase, so in this type of outboard motor it has to be placed inside the casing due to space issues, so the oil pan is located at the top of the casing. It will be fixed in a state where it is largely inserted into the space of. In this case, the mounting structure for the internal combustion engine is to attach a spacer to the top opening of the casing so as to close it, place and fix the internal combustion engine on top of this spacer, and suspend the oil pan from the bottom surface of this spacer. A supporting structure can be considered. When this mounting structure is adopted, it is necessary to provide a return hole in the spacer for returning oil, which communicates the inside of the oil pan with the inside of the crankcase or cylinder head of the internal combustion engine. Since this type of outboard motor is mounted on the transom of a boat via a bracket, it may be rotated to a tilted-up position or may be held in this tilted-up position. As a result, the mutual positional relationship between the oil pan and the internal combustion engine changes, and the lubricating oil stored in the oil pan tends to flow into the cylinder head and crankcase through the return hole. In this case, there is no problem with the lubricating oil flowing into the crankcase, but if a large amount of oil flows into the cylinder head, there is a risk that the lubricating oil will enter the intake and exhaust valves and the valve mechanism, causing oil leakage. This will have a negative effect on the engine.

The present invention was made based on the above circumstances, and its purpose is to prevent the lubricating oil in the oil pan from seeping into the cylinder head even when the outboard motor is tilted up. The aim is to provide an outboard motor that can prevent problems before they occur.

That is, in order to achieve the above object, the present invention
The spacer to which the internal combustion engine and oil pan are attached has a small hole located forward of the cylinder head of the internal combustion engine when the outboard motor is tilted down, and below the cylinder head when the outboard motor is tilted up. This is characterized in that the inside of the oil pan communicates with the inside of the crankcase and cylinder head through this small hole.

The present invention will be explained below based on an embodiment shown in the drawings.

In the figure, reference numeral 1 denotes an outboard motor, which is attached to a transom 4 of a hull 3 via a bracket 2. The outboard motor 1 is rotatably supported around a pivot shaft 5 passing through a bracket 2 from a tilt-down position shown by a solid line to a tilt-up position shown by an imaginary line. The posture is maintained through a reverse lock mechanism and a tilt lock mechanism (not shown). Further, it can be rotated left and right about a pivot shaft (not shown) inserted through the swivel bracket 6, and has a rudder function. This outboard motor 1 has an aluminum alloy Atsupa casing 7.
A cowling 10 is attached to the upper end of a casing 9 formed by connecting the upper casing 7 and the lower casing 8, and an exhaust guide 11 is attached to the upper opening of the upper casing 7.
Exhaust guide 11 is Atsupa casing 7
It has a shape that matches the upper end opening, and closes the upper end opening of the upper casing 7 to form the casing 9.
The inside and the inside of the cowling 10 are divided. The engine 12 is mounted on the top of the exhaust guide 11.
The engine 12 is housed within the cowling 10. The engine 12 is a water-cooled four-stroke two-cylinder engine, and a cylinder block 13 includes a pair of cylinders 14.
The cylinders 14a, 14b are arranged vertically in parallel, and each cylinder 14a, 14b is provided with its cylinder axis extending in the front-rear direction. Each cylinder 14a,
Sleeves 15, 15 are attached to the inner surface of 14b, and pistons 16, 16 are accommodated within these sleeves 15, 15. The front end surface of the cylinder block 13 is provided with a crank case 17.
are connected to each other, and inside this crankcase 17 is a crank chamber 18 connected to the cylinders 14a and 14b.
is doing. A crankshaft 19 along the vertical direction is pivotally supported in the crank chamber 18, and
Crank pins 20, 20 of the crankshaft 19 are connected to the piston 1 via connecting rods 21, 21.
6 and 16. This crankshaft 19
The upper end of a drive shaft 22, which is inserted vertically inside the casing 9 and rotatably passed through the front end of the exhaust guide 11, is engaged with the lower end of the drive shaft 22 by a spline. A propeller 24 is rotatably driven via a propeller shaft 23. Further, a cylinder head 25 is attached to the rear end surface of the cylinder block 13, and combustion chambers 26, 26 are formed in the cylinder head 25, and are connected to the respective cylinders 14a, 14b. A head cover 2 is attached to the rear end surface of the cylinder head 25.
A camshaft 29, which opens and closes an intake valve and an exhaust valve (not shown), is pivotally supported along the vertical direction in a camshaft housing chamber 28 formed between these. Further, an oil pump 30 that is rotatably driven by a camshaft 29 is built into the lower end of the cylinder head 25, and a suction port of this oil pump 30 is connected to the cylinder block through a suction passage 31 in the cylinder block 13. 13, that is, the abutting surface with the exhaust guide 11, is connected to a suction port 32. and oil pump 30
The discharge port is connected to a first oil delivery passage 33 provided below the lower cylinder 14a, and the tip of this first oil delivery passage 33 is connected to the crankshaft 1.
9 is connected to the lower end shaft support. Further, a second oil delivery path 34 is provided above the upper cylinder 14b. This second oil delivery path 34 and the first oil delivery path 33 are connected to a communication path 35 provided in the cylinder block 13 along the vertical direction.
communicated via. Second oil delivery path 3
One end of 4 is connected to the upper end shaft support of the crankshaft 19, and the other end is connected to the upper end shaft support of the camshaft 29. Furthermore, an exhaust outlet 36 is opened on the lower surface of the cylinder block 13 and is connected to the exhaust ports of the combustion chambers 26 , 26 . A recess 37 is adjacent to the exhaust outlet 36 .
is recessed. A communication port 38 connected to the crank chamber 18 is opened at the front bottom of the recess 37, and this recess 37 is connected to the cylinder block 13.
The camshaft housing chamber 28 communicates with the lower part of the camshaft housing chamber 28 through oil outflow holes 39 and 40 formed at the lower part of the abutment surface between the camshaft housing chamber 28 and the cylinder head 25. Screw holes 41 are provided at multiple locations on the bottom surface of the cylinder block 13 and crankcase 17.
... are provided in the exhaust guide 11, and the insertion holes 42 ... are opposed to these screw holes 41 ....
has been established. This exhaust guide 11
Bolts 43 are inserted into the insertion holes 42 from the casing 9 side, respectively.
... is screwed into the screw hole 41... and the cylinder block 1 is screwed into the cylinder block 1.
3 and a crankcase 17 are coupled onto the exhaust guide 11. Therefore, the engine 12 is rigidly mounted on the upper surface of the exhaust guide 11.

On the other hand, a joint surface 44 (the portion hatched with broken lines in FIG. 7) is formed approximately at the center of the lower surface of the exhaust guide 11.
An oil pan 45 for storing engine oil is attached to. The oil pan 45 has a substantially cylindrical shape with a bottom, and its upper open end surface abuts the joint surface 44, and is connected by a plurality of bolts 46. Therefore, oil pan 45
is suspended and fixed to the lower surface of the exhaust guide 11, and enters into the upper space of the upper casing 7.

Thus, approximately in the center of the exhaust guide 11, there is an exhaust port 47 connected to the exhaust outlet 36, and an oil return hole 4 located in front of the exhaust port 47.
8 are opened, and these exhaust ports 47 and oil return holes 48 are located inside the joint surface 44. The oil return hole 48 communicates between the inside of the recess 37 of the cylinder block 13 and the inside of the oil pan 45, and is formed to be much smaller than the opening area of the upper end opening of the oil pan 45. The oil return hole 48 is located at the front end portion of the oil pan 45 and further forward than the oil outflow holes 39 and 40 that communicate the recess 37 and the camshaft housing chamber 28 . Therefore, when the outboard motor 1 is tilted up as described above, the oil return hole 48 is positioned below the oil outflow holes 39 and 40. Note that in FIG. 3, symbol A indicates the oil level of the engine oil in the oil pan 45 in the tilted-down state, and symbol B indicates the oil level in the tilted-up state.

A drain hole 49 is formed in the bottom of the oil pan 45, and the bottom of the portion where the drain hole 49 is formed is located on a bulge 50 that bulges out rearward on the rear surface of the upper casing 7. 51. And in the bulging part 50,
A through hole 52 is formed to face and match the drain hole 49, and a drain bolt 53 is screwed into the drain hole 49 through the through hole 52. Approximately at the center of the oil pan 45, an exhaust pipe passage 55 is provided along the vertical direction and is separated from the interior of the oil pan 45 by a partition wall 54.
The upper end opening of 5 is connected to the exhaust port 47 of the exhaust guide 11. An exhaust pipe 56 is attached to the lower opening of the exhaust port 47, and the exhaust pipe 56 is loosely inserted into the exhaust pipe passage 55, and its lower end is led out into the upper casing 7. The front end portion of the partition wall 54 is integrally continuous with the inner surface of the oil pan 45, and a cooling water passage 57 is provided in this portion along the vertical direction. The upper end opening of the cooling water passage 57 is connected to the cylinder block 13 and the cylinder head 2 through a communication hole 58 formed in the exhaust guide 11.
It is connected to the water jacket 59 inside 5.
A water tube 61 is connected to the lower end opening of the cooling water passage 57 via a seal 60, and this water tube 61 is connected to water inlets 62 on both sides of the lower casing 8 via a water pump (not shown). It is connected to...

Note that reference numeral 63 is a suction pipe for sucking engine oil stored in the oil pan 45, and is connected to the suction port 32 of the cylinder block 13.

According to such a configuration, the engine oil stored in the oil pan 45 is pumped into the suction passage 31 via the suction pipe 63 when the oil pump 30 is started, and then pumped into the first suction passage 31. The oil is fed under pressure into the oil delivery path 33. Then, this engine oil is also guided into the second oil delivery path 34 via the communication path 35, and is first introduced into the crankshaft 19.
After lubricating the oil, the oil is guided from the lower part of the crank chamber 18 through the communication port 38 into the recess 37, and from there is returned into the oil pan 45 through the oil return hole 48. Further, a part of the engine oil guided to the second oil delivery path 34 is transferred to the camshaft 2.
9, and after lubricating the entire camshaft 29, it falls to the lower part of the camshaft housing chamber 28 and remains there. This retained engine oil is
The oil flows out into the recess 37 through the oil outflow holes 39 and 40, and from there returns into the oil pan 45 through the oil return hole 48.

By the way, when you tilt up the outboard motor 1,
Since the entire body is tilted forward, the position of the engine oil level in the oil pan 45 also changes as shown in FIG. 3, and the oil return hole 48 and the oil level become close to each other. Then, when the shock is tilted up or when the hull 3 rocks, for example, the oil surface becomes rippled, and together with the above-mentioned inclination, the engine oil flows back into the recess 37 through the oil return hole 48. Since this recess 37 communicates with the crank chamber 18 and the camshaft housing chamber 28 as described above,
In the conventional structure, the oil that flows back flows into the crank chamber 18.
It is conceivable that the particles may enter the camshaft housing chamber 28. In this case, there is no problem with the engine oil flowing into the crank chamber 18, but if it flows into the camshaft housing chamber 28, there is a risk that the oil may drop.

However, in the embodiment according to the present invention, the oil return hole 48 is located in a portion located forward of the oil outflow holes 39, 40, that is, in a portion located below the oil outflow holes 39, 40 and the camshaft housing chamber 28 at the time of tilt-up. Since the engine oil is provided in the recess 37, the engine oil flows through the oil outflow holes 39 and 4.
There is no risk of the engine oil flowing out toward the 0 side, and since the oil return hole 48 has a smaller diameter than the opening area of the upper end opening of the oil pan 45, a large amount of engine oil flows into the recess 37 at once. No need to worry. Therefore, a large amount of engine oil does not flow into the camshaft housing chamber 28, and engine troubles due to oil drop etc. can be prevented.

Note that the engine according to the present invention is not limited to two cylinders, and can be similarly implemented even if it is a single cylinder engine or a multi-cylinder engine with three or more cylinders.

The present invention described in detail above has a spacer attached to the upper end opening of the casing to partition the inside of the casing and the inside of the cowling, an internal combustion engine mounted on the spacer, and an oil containing lubricating oil on the lower surface of the spacer. The pan is attached, and the spacer has a small hole located below the cylinder head of the internal combustion engine when the outboard motor is tilted up. It communicates with the inside of the head. According to this product, even if the outboard motor is tilted up, a large amount of lubricating oil will not flow back into the cylinder head at once, and therefore, problems such as oil leakage can be prevented. It has a great effect.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view of an outboard motor, FIG. 2 is a cross-sectional view showing how the internal combustion engine and oil pan are attached to the spacer, and FIG.
The figure is a cross-sectional view showing how the oil pan is installed. Figure 4 is a bottom view of the oil pan attached to the spacer, seen from the casing side. Figure 5 is the same view of the internal combustion engine attached to the spacer, viewed from the casing side. FIG. 6 is a view showing the surface fixed to the spacer of the internal combustion engine, FIG. 7 is a bottom view of the spacer, FIG. 8 is a sectional view taken along the line - in FIG. 7, and FIG. It is a top view of an oil pan. DESCRIPTION OF SYMBOLS 1... Outboard motor, 9... Casing, 10... Cowling, 11... Spacer (exhaust guide), 12... Internal combustion engine (engine), 17... Crank case, 25... Cylinder head, 45...
...Oil pan, 48...Small hole (oil return hole).

Claims (1)

[Claims] 1. In an outboard motor in which a cowling is provided at the upper end of the casing and an internal combustion engine is disposed within the cowling, a spacer is attached to the upper end opening of the casing to partition the inside of the casing and the inside of the cowling, and the internal combustion engine is mounted on the spacer. At the same time, an oil pan for storing lubricating oil for the internal combustion engine is attached to the lower surface of the spacer, and the spacer is located forward of the cylinder head of the internal combustion engine when the outboard motor is tilted down. An outboard motor characterized in that a small hole is provided below the cylinder head in a tilted up state, and the small hole communicates the inside of the oil pan with the crankcase and the inside of the cylinder head of the internal combustion engine. .